The present invention relates to a spring rewound tagline device, and more particularly to a mechanism for controlling unwinding of the spring in a spring rewound tagline device.
Spring loaded tagline rewound devices for use with cranes, and the like, have heretofore been known generally from U.S. Pat. No. 2,303,002, issued Nov. 24, 1942 to W. J. Ruddock, and U.S. Pat. No. 2,645,432, issued July 14, 1953, and Pat. No. 3,062,479, issued Nov. 6, 1962, both to H. V. Griffitts, which employ a coiled torsion spring connected between a movable core and a hollow, generally cylindrical housing surrounding the core to supply the power that rewinds a tagline, electrical cable, and the like, onto a reel operatively connected to the movable core. By anchoring the coiled torsion spring at one end to a fixed element, such as the housing of the device, and at the other end to a rotatable part, such as the reel by means of the core, the spring is wound, or tensioned, responsive to rotation of the reel in one direction so as to resiliently rewind the reel in an opposite direction as the load on the tagline, or other cable, is relieved.
A problem encountered with such conventional tagline devices, however, is that a substantial amount of tension may remain on the spring when it is necessary or desirable to perform maintenance or repair work on the tagline device, or detach it from a controlled device. The presence of such tension on the spring is inherently dangerous to the personnel performing such maintenance and/or repair work, and creates a definite safety hazard. Further, doubt as to the amount of tension remaining on the spring requires at least three men to perform a disengagement of a tagline or electric cable from a bucket, magnet, or similar implement being controlled and actuated by the tagline device. It is therefore a customary practice to always position one man adjacent the reel, or reels, associated with the tagline device for placing, and subsequently removing a wood block, and the like against a gusset provided on the interior side of the cable reel, while two men are required to safely walk-in the cable. As will be appreciated, this procedure is inefficient, time consuming, and expensive.
Accordingly, the present invention proposes to provide a brake arrangement for controlling or regulating the unwinding of the spring, and accompanying rewinding of a tagline or other cable on the reel.
U.S. Pat. Nos. 2,283,784 and 2,382,955, issued May 19, 1942 and Aug. 21, 1945, respectively, to R. O. Billings, disclose tagline reels of the coiled torsion spring type which employ a brake band and drum assembly to retard movement of the reel when the tagline is being payed-out. These brake assemblies are intended to release when the torsion spring is rewinding the tagline onto the reel, and accordingly are unsuited for holding the reel against movement, or controlling the unwinding of the torsion spring during rewinding of the tagline or cable on the reel.